An exhaust gas recirculation (EGR) system may be included in a combustion engine to reduce combustion temperatures and lower emissions. In one example, under selected conditions, an EGR system may exclusively couple an exhaust manifold of a first group of cylinders to an intake manifold of an engine, and not to the atmosphere. Such cylinders are referred to as donor cylinders. By providing EGR to an intake in such a manner, the effective oxygen content of the intake air may be reduced, thus lowering the combustion temperature and reducing production of emissions such as NOx.